Explosive-operated shears



R E K R A B A GM EXPLOSIVE-OPERATED SHEARS mi; ron 1, 19

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NITD AENT OFFICE The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

'I'he invention relates to exp1osiveoperated toolsand more particularly to a wire-cutting tool l adapted to be detachably connected to a shoulder arm. so as to be operated by the discharge thereof. It is an aim of the invention to provides. wire shears tool of a particularly rugged nature liable` in a minimum degree to damage or derangement in the unusually fast and rough actioninvolved in an attack against barbed wire guarded positions under an enemys defensive fire. f

It is particularly an aim to oifer a tool of great power, eective on very heavy wire and the like. if necessary.

4A further purpose is to present a novel and desirable specific structure for attaining the objects stated and others.

Additional objects, advantages and features yof invention reside in the contruction, arrangement and combination of parts involved in the embodiment of the invention, as will be more clearly apparent from the following description and accompanying drawings. wherein:

Figure 3 is a section on the line 3 3 of Figure 2;"

Figure 4 is a cross section on the line 4-4 of Figura 2;

Figure 5 is a cross section on the line 5 5 of Figure 2:

. Figure 6 is across section onfthe line 8 6 of Figure 2;

Figure 7 is a cross section on the line 'I-1 of Figure 1: s Y

Figure 8 is a perspective view of the rear sleeve:

Figure 9 is a top view of the sleeve-cylinder, the cylinder being in section.

Figure 10 is a perspective view of a modiiication of the piston slotted at its inner end so as to keep the ports open initially.

There is illustrated a carbine I0 of conventional form upon which my invention is incorporated, although my invention may be applied to other weapons. This arm includes a gunstock II, of usual form, on which a barrel I 2 is mounted, projected forwardly from the hand rest portion -I3 o1' -the stock, and secured to the forward end of the stock by a frontstock ferrule IB. Any approved loading and ring mechanism may be employed,

amended April 30, 1928: 370 0. G. 757) 2 the details of which are not illustrated, although semi-automatic re `mechanism is eii'ective with the invention andis commonly employed in the weapon illustrated, using .30 caliber blank ammunition. i

In the present instance a wire-cutting shears is illustrated, consisting of a -base jaw or-blade I5 with anintegral rectilinear shank I 6 extending rearwardly and adapted to lie closely parallel to the barrel I2 as shown. The base of the blade I5 is deiined by a horizontal'pivot Vstud I1 upon which a working blade I8 is pivoted; 'I'he blade I5 and shank may be planiform and of uniform thickness throughout, with a. continuous rectilinear top edge I9 throughout. The blade and shank are arranged with the top edge slightly below the -barrel land with the blade in a vertical plane spaced a distance toward the left from the axis Vof the barrel bore 20. The blade I 5 is formed with a at inner side 2I arranged to receive a corresponding side 22 of the working blade flatly thereagainst,

the stud I'I being headed suitably to hold the blades in proper assembly relation. 'I'he working blade is formed with a cam heel end 23 extending upwardly beyond the axis of the barrel, the

blade being arranged in a diametrical plane of the barrel. The blade I8 has a short shank 24` extending downwardly and having a pivot opening therethrough extending partly below the cut ting edge 25 (which is the lower edge of the blade). Through this opening the pin I1 is engage'd.

The rear or cam face 26 of the heel 23 is slightly curved and extends upwardly with a forward inclination approximating a radius at an angle of between iive and ten degrees to a vertical radius of the pin I'I when the blade is at its lower full stroke limit of movement as dotted in Figure 2. The top of the cam faceextends above the a'xis of the bore 20 a substantial distance throughout the full movement of thel blade from open to closed position.

A rearwardly extending lug or wiper 2'I is formed on the lower part of the shank 24, and a leaf spring 28 is mounted on the shank I6, a forward end of the spring being disposed over the wiper, so as to press downwardly thereon and hold the blade yieldingly in elevated open position. The spring tends to assume a rectilinear form, its rear end being anchored by a stud 29 `on the shank I6, while a middle seat stud 29' is set in the shank I6 soas to hold the spring'bcrwed downward causing its proper reaction against thewlperlug 21.

A barrel engaging sleeve 30 and enlarged piston acaaaea 3 chamber or cylinder Slgformed concentricaliy-in one piece are provided, secured to the shank I6, the sleeve and gun barrel being constructed to permit engagement and securement of the sleeve on the barrel removably so that the latter communicates coaxially with the cylinder.` While various `quick-detachable constructions may be employed forcoupling the device to the barrel, including bayonet joints or connectionsin the present instance Ihave shown the barrel exteriorly threaded and the sleeve interiorly threaded at the rear part and screwed on to the barrel. a iiat 82 being formed at the top of the barrel extending longitudinally over part of the threaded portion of the barrel, and in the sleevethereover a radial slot 33 is formed. a key 34 being provided to nt in the slot for radial sliding movement therein. and of such radial dimension that when Vresting on the iiat.- the outer part of the key is flush with the periphery of the sleeve. A split cylinder clasp 35 is fitted slidably and frictionally on the sleeve. holding the key in place. The enlargement of this mounting around the cylinder aiiords a shoulder 36 which limitsforward movement of the clasp. The lower side of the latter is yopen suiiiciently to clear the shank IB amplyas in Figure 5. In the present instance the sleeve and cylinder member is secured to the upper right hand angular edge of the shank i6 by a longitudinal bead of welding at each side, the shank being slightly relieved (as in Figure 4) beside the cylinderto receive the same with the sleeve lying close against the unrelieved angular edge of the shankas-in Figureand 6.

*In order toseiirethe rear end of the shank i6 A infirm and safe relation to the barrel. I provide a base sleeve 315 (liigs.` 1, I and 8). which is a j' double sleeve, having a lower left hand tube 38 rectangular in cross section and fitted snugly and slidably to the shank I8. and an upper cylindrical sleeve slidabie von the barrel, the rear end of this being transversely cut across the top to form a clamp arm lll. out-turned clamp ears 4l being formed on the 'end of the arm 40 and on the unslit partof Vthe sleeve. both ears being apertured and receiving a bolt 42 thereacross with nut at one end. by which the sleeve. is clamped in place to vsecure the shank I6 against lateral'displacement. In this instancethe rear end ofthe sleeve 31 is enlarged to receive as a socket the forward ex- ?-tremity of the stock. `,the eccentricity of which serves to prevent the sleeve from rotating on the 'Y barrel when the sleeve is at its rear limit of sliding movement. It will thus be seen that with the sleeve 31 secured at its rearmost position, the

sleeve 31 cannot be rotated for disengagement. The key device 34 is an additional safety feature, making a very rigid. rugged mounting. The sleeve 31. the shank it and sleeve 35 ineifect combine vwith the barrel to constitute a supporting frame.

Between the threaded opening in the sleeve 30 and cylinder an interior shoulder 4t is formed, against which the end of the barrel l2 abuts when the sleeve is screwed home, and a barrel part 45 is thus provided slightly larger than the '4 for proper reciprocation and working therein of a piston lll. which is itself bored as at is from the rear end to a diameter approximately twice the diameter of the gun bore 20. The length of the bore 48-in the piston is approximately four and one-half calibers. and with the cylinder constitutes an expansible chamber 49. the piston initially being engaged against. the shoulder M and having a head 50 formed with a curved end face lil against which the heel cam face 26 engages -as a stop with the working blade in open position as in Figure 2. The faces 26 and 5i may be otherwise shaped as may be indicated to best apply longitudinal pressure of the piston against the heel 23 with a minimum of lateral resultants of force acting crosswise of the piston head.

The piston is formed with two parallel ears 52 extending forwardly close and slidably beside the n `hitter.

bore 20 but iiared longitudinally toward the cyl- The cylinder has a lateral port 63 formed in each side thereof. consisting of a narrow slot extending ',circumierentially over-an angle of somewhat more than ninety degrees at the interior cylinder wall. in a plane normal to the axisiof the cylinder; the narrow dimension of the slot extending longitudinally of the cylinder and its extent in each dimension depending on the rate of escape of gases desired under operation oi the devices. and it may be adapted to the amount of explosive used, and the interval in which desired work is to be performed. The slot is spaced a short distance forward from the shoulder 44 so that it will be uncovered after a short movement of the piston. These ports may be varied in proportions. arrangements. and contours to vary the time of high pressure action of the device and at the same time assure prompt venting of gases and return of the tool to initial condition ready for repeated operation. The forward and rear faces Eil- 5 5 of the ports in this instance are sloped rearwardly toward the outside Aso that upon discharge of products of combustion through the chamber the gun and tool will be thrust forwardly by the reaction of the gases through the ports. and the A tool held effectively pressed to the work,

If desired (as in Figure 10).. the piston 4l' may be shorter than shown in Figure 2, and provided with extensions 56 at top and bottom clear of the ports 53 to hold the piston clear of the ports when the piston is in initial position. The device may otherwise be the same as before described.

The tool shown is provided with one or more notches 5l in one of the blades-to prevent work I from slipping forward between the blades while they are closing.

In use. the device being constructed and assembled as in Figures 1 to 8, the loading and firing mechanism of the gun is supplied with blank cartridges with suitable charges of explosive to supply the energy required This is possible by inserting a conventional magazine or clip 88 in vthe receiverof the gun in a'well known form.

The soldier assigned to Wire cutting approaches the fence. entanglement. or other wire obstruction, or material to be cut and thrusts the gun -forward so as to receive between the blades ll-l 8 a strand or a number of strands or bars of the material to be cut. and presses the tool forwardly so that the material is firmly pressed into the angle at the intersection of the opposed edge of the two blades.

The notches 51 will serve to hold such engaged the cylinder. The length of this bore is suihcient material in place when the blade is closes. The

Vaccanita trigger of the gun is then'operated to discharge a cartridge in the conventional way. The products of the explosion pass forwardly through the blade I8.' The curved face 5| on the piston presses and wipes against the heel cam face 2'8 effecting the desired movement or stroke of the blade I8 from full open position :to fully closed ppsition. In view of this action the device may be classed as a full stroke tool. At the same time, after `a short movement of the piston, the ports 53 are uncovered and the backward blast thus produced thrusts the gun and tool forwardly so that tendency of the tool to backl off by the rearward force resultants of the closing of the shears u'pon the work is'opposed, and also ythe forward thrust of the gun .will also tend to prevent escape of the work if the latter tends to move forwardly by the ei ect of the force resultants mentioned.

The operator continues pressing the gun and tool forwardly after the first operation of the trigger and as soon as a sumcient further quantity of material is gathered between the blades, another cartridge is iired, and the operations repeated as required.

By having the ports 153 initially uncovered, forming the piston as in Figure 10, ythe forward thrust or kick of the gun will occur earlier and will be sustained in proportion to the volumetric value and burning characteristics of the explosive used.

While I have disclosed the invention in its best form thus far perfected by me, it will still be understood that this is exemplary and that changes in form and proportions, construction, arrangement, and combination of parts, substitution of materials and equivalents, mechanical or otherwise, may be made to carry out the intent of the invention without departing from the spirit of the invention.

The enlarged size of the chamber within the piston aiIords a cushioning means, preventing too abrupt a build-up of pressure in the barrel. This will obviate the need for special slow burning propellant, and also will enable mak-ing the tool lighter, as otherwise the parts may have to be made stronger and consequently heavier to avoid deformation by propellants which are .too fast burning. l

In order to dismount the tool, the rear or base sleeve 3l is released by unscrcwing .the bolt 42, and the clasp 35 moved slidingly rearward, uncovering the key 34. The sleeve 30 may then be rotated counterclockwise on the barrel, to unscrew it from the barrel, the fiat 32 serving as a cam to force the key outward. This feeds the whole tool assembly from the gun. Ihe front sight may then be replaced if i-t has beenremoved..

The invention may be readily adapted to other forms of tools, and, in those where sustained pressure against the work is a material factor (which may be termed pressure effective too1s) the inclination of the portsrdescribed makes it specially valu able.

I claim: 1. A shears device, in combination with a gun having a barrel provided with a muzzle, compris` lection of thebarrei and positioned to swing in 'a plane alined with the bore of 4the barrel, means responsive to gas discharge from the barel to operate, the working blade full stroke in one direction, a longitudinal bar spring mounted on the shank having a forward end adjacent the pivot of the blade, said working blade having a lug thereon arranged to engage .the outer side of the spring, said spring being under tension to l'fbear on said lug and hold the working blade' s tiem, a cylinder xed in coaxial gas receiving relation to the gun muzzle, a piston slidable in the cylinder and contacting the moveable shear blade, the cylinder being formed with lateral ports near its rear end of small dimension longitudinally of the tool and more extensive circumferentially, the forward and rear sides of the ports being-inclined rearwardly whereby vented gases will react against the device to thrust it forwardly against the work.

3. A wire cutting attachment. in combination with a gun having a barrel provided with a muzzle, comprising a frame having a releasable gun barrel connection, ,a cylinder at the forward part thereof, said cylinder having a lateral vent port open at its forward end and open at its rear end in gas receiving relation to the said gun muzzle, a hollow piston reciprocable in the cylinder, the said piston having a closed forward end and an interior at least two calibers diameter and four calibers length and open to the bore of the said barrel, movable forwardly to clear said port, a

stationary shear jaw carried by said frame extended longitudinally at the front of the attachment, a cooperative shear jaw pivoted thereto on a transverse axis oifset from the cylinder, said shear jaw having a part extended into the path of the piston and moving longitudinally therefrom in closing movement of the jaw, and resilient means to hold the last named jaw in open position.

4. The combination with a gun having a barrel provided with a muzzle, of a shear attachment comprising a tubular member constructed for and engaged on the muzzle of the said gun, said member being enlarged an'd bored to form a longitudinal cylinder before and larger than the said gun bore and having a rear gas receiving port arranged to align with the gun bore, a hollow piston slidable in the cylinder having a forward head and an open rear end whereby to form a chamber in said cylinder and piston larger in diameter than the gun bore, a lateral port being formed intermediately of the length of the limits 0f movement of the rear end of the piston, a shear blade xed with the cylinder and projected longitudinally forward therefrom, an operating blade co,. operative with the flxed blade and pivoted thereon on a pivot axis spaced from the axis of the cylinder, the operating blade aligned with the cylinder, said operating blade having a heel part extending across the path of the piston and resting against the piston head when .both are at the rear limits of their movements and open position of the operating blade, the forward longitudinal movement of the heel part being limited to prevent the piston from clearing the cylinder while in operai 1 i tion. and resilient means tohold the operating blade in onen position.

' Y5. In combination wlth a ilrearm having a stock and a barrel, a shear member forward oi the munie and having a shank extending along the barrel, a ferrule having portions tted on the barrel and shank for sliding motion thereon and having a portion complementary to the forward portion of the stock and means to, clamp said latter portion to the stock, a sleeve on said shear member, means to nx said sleeve member on the muzzle end of the barrel, a second shear member arrana'ed for cutting action with the rst shear member. and means responsive to gases in the barrel to actuste said shear members.

GEORGE A. BAKKER.

nEFnnENoEs y crrnn Number Number l UNITED STATES PATENTS Name Date Pell etal Aug. 7, 1900 McClean Mar. 28, 1905 Holm May 2, 1916 Steinmetz Jan. 9, 1917 Du Pont May 27, 1919 v Cutts July 19, 1927 Miller June 27, 1933 FOREIGN P ATENTS Country Date Great Britain 1915 Great Britain 1915 Germany June 5. 1915 

